During treatment and follow-up of either GTD or GTN, contraception is recommended since it would be difficult to distinguish between a new pregnancy or recurrent disease. If the patient does not have contraindications to hormonal treatments, OCPs are generally recommended. Intrauterine devices (IUDs) should be avoided at least until hCG is negative since there is a risk of uterine perforation.
Patients can sometimes have phantom (or false positive) hCG. In these cases, hCG can be elevated up to a few hundred but they are not secondary to a GTD/GTN. This has been described in patients who have heterophile antibodies that are detected by hCG assays as well as in postmenopausal women who have increased levels of LH that cross-reacts with hCG assays.
There are different strategies to determine whether the elevated hCG is a false positive result:
- Repeat the test in the same lab (to ensure correct reading);
- Repeat the test in a different lab;
- Do urinary pregnancy test (if it is a true elevation of hCG, the urine test should be positive);
- Proceed with serial dilutions of the serum (with serial dilutions, the hCG level should decrease);
- Test for heterophile antibodies;
- Trial of oral contraceptives (OCP) in postmenopausal women and repeat hCG test after (should suppress the production of hCG-like polypeptide by the pituitary).
Up to 10-15% of patients will develop an arteriovenous fistula after GTD/GTN but only 2% will be symptomatic from it. Angiography represents gold standard procedure for diagnosis but it can also be diagnosed with Doppler ultrasound or MRI. If symptomatic, these can be managed by hormonal manoeuvres, embolization, surgery (hysterectomy, laparoscopic resection, uterine/internal iliac artery ligation).
